I know Dayton is an hour from Columbus or so... how much further to Cincy? Another hour?

With no traffic, downtown Columbus to downtown Cincinnati is maybe a smidge under two hours. Obviously staying in Cincinnati and going to Columbus for gameday will necessitate way more time than that (if the OSU game is announced for noon, I will seriously consider a hotel in Columbus Friday night). If you were in Columbus and heading to Cincinnati for the Sunday NFL game, I'd plan about 2:15 from departure to parking lot.

I think a few folks here should stay around Cedarville college so they can see how it's NOT greater Cincinnati.